dopamine-release-at-individual-presynaptic-terminals-visualized-with

Dopamine Release at Individual Presynaptic Terminals Visualized with FFNs

The nervous system transmits signals between neurons via neurotransmitter release during synaptic vesicle fusion. To observe neurotransmitter uptake and ...

The goal of this work was to shed more light on a preliminary finding about the relationship between the substitution in the thioacyl part of thiobenzanilides and their antituberculous effect. Thus, we prepared a set of 14 derivatives, out of which eight had not yet been reported, and the compounds were evaluated for antimycobacterial activity on a panel of four Mycobacteria species, including Mycobacterium tuberculosis CNCTC My 331/88, Mycobacterium kansasii CNCTC My 235/80, Mycobacterium avium CNCTC My 330/88 and M. kansasii 6509/96. While the contribution of the substituents with differing electronic and lipophilicity characteristics in position 3 to the antituberculous activity was negligible, we found that unsubstituted position 4 in the thioacyl part appears to be a prerequisite for a thiobenzanilide derivative to possess appreciable biological activity.

On the relationship between the substitution pattern of thiobenzanilides and their antimycobacterial activity.

Zur Beziehung zwischen dem Substitutionsmuster thiobenzanilides und ihre antimykobakterielle Aktivit&#xE4;t.

Two series of 3-(substituted phenyl)-5-alkyl-2,5-dihydrofuran-2-ones related to a natural product, (-)incrustoporine, were synthesized and their in vitro antifungal activity evaluated. The compounds with halogen substituents on the phenyl ring exhibited selective antifungal activity against the filamentous strains of Absidia corymbifera and Aspergillus fumigatus. On the other hand, the influence of the length of the alkyl chain at C(5) was marginal. The antifungal effect of the most active compound against the above strains was higher than that of ketoconazole, and close to that of amphotericin B. In order to verify the hypothesis about a possible relationship between the Michael-accepting ability of the compounds and their antifungal activity, a series of simple carbanalogues, 2-(substituted phenyl)cyclopent-2-enones, was prepared and subjected to antifungal activity assay as well.

Synthesis and structure-antifungal activity relationships of 3-aryl-5-alkyl-2,5-dihydrofuran-2-ones and their carbanalogues: further refinement of tentative pharmacophore group.

Synthese und Struktur-Aktivit&#xE4;ts-Beziehungen antimykotische von 3-Aryl-5-alkyl-2 ,5-dihydrofuran-2-one und deren carbanalogues: weiteren Ausgestaltung der vorl&#xE4;ufigen Pharmakophor-Gruppe.

A new fluorogenic substrate was developed for 3alpha-hydroxysteroid dehydrogenases (3alpha-HSD), including the human enzymes implicated in important physiological functions (androgen deactivation, neurosteroid activation). While ketone 5 is nonfluorescent, the corresponding alcohol exhibits high fluorescence with emission maximum at 510 nm, thus constituting a redox optical switch. This study began with a chemical concept of a ketone-alcohol optical switch which guided the synthesis of a focused array of compounds. Subsequently, seven compounds were selected (1-7) on the basis of their optical and chemical (stability) properties and were submitted to a screen against a panel of dehydrogenase enzymes. Probe 5 was found to be highly selective for bacterial, rat, and human 3alpha-HSD enzymes. The kinetic parameters were obtained for human 3alpha-HSD enzyme (type 2 isozyme, AKR 1C3; Km = 2.5 muM, kcat = 8.2 min-1). Remarkably, comparison to 5alpha-dihydrotestosterone (5alpha-DHT, Km = 26 muM, kcat = 0.25 min-1, Figure 4), a likely physiological substrate in prostate, revealed that synthetic probe 5 is in fact a far better substrate for this enzyme. Structure 5 represents an exciting lead for the development of a redox imaging probe.

New tools for molecular imaging of redox metabolism: development of a fluorogenic probe for 3 alpha-hydroxysteroid dehydrogenases.

Neue Werkzeuge f&#xFC;r die molekulare Bildgebung von Redoxmetabolismus: Entwicklung eines fluorogene Sonde f&#xFC;r 3 alpha-Hydroxysteroiddehydrogenasen.

Die Zwei-Photonen induziert Uncaging einer reaktiven Zwischenstufe. Multiphotonen in-situ-Detektion eines potentiell wertvolle Label f&#xFC;r biologische Anwendungen.

[reaction: see text] Two-photon induced Wolff rearrangement of a terphenyl diazoketone 1 was achieved by using focused laser pulses of 532 nm from a Q-switched Nd:YAG laser. The nonfluorescent terphenyl diazoketone 1 was transformed into a fluorescent ester derivative 4, which can be detected in situ using the focused laser pulses at 532 nm. Laser power dependence studies show that the Wolff rearrangement is induced by two-photon absorption of the terphenyl diazoketone 1, but suggests that more than two photons of 532 nm are involved (a multiphoton process) in excitation of the ester derivative 4.

Two-photon induced uncaging of a reactive intermediate. Multiphoton in situ detection of a potentially valuable label for biological applications.

The current arsenal of tools and methods for the continuous monitoring and imaging of redox metabolic pathways in the context of intact cells is limited. Fluorogenic substrates allow for direct measurement of enzyme activity in situ; however, in contrast to proteases and exo-glycosidases, there are no simple guidelines for the design of selective probes for redox metabolic enzymes. Here, we introduce redox probe 1 and demonstrate its high selectivity in living cells for human hydroxysteroid dehydrogenases (HSDs) of the aldo-keto reductase (AKR) superfamily. AKR1C isoforms perform multiple functions among which the metabolism of potent steroid hormones is well documented. Moreover, expression of these enzymes is responsive to cellular stress and pathogenesis, including cancer. Our probe design is based on redox-sensitive optical switches, which couple a ketone-alcohol redox event to a profound change in fluorescence. The high selectivity of phenyl ketone 1 for AKR1C2 over the many endogenous reductases present in mammalian cells was established by a quantitative comparison of the metabolic rates between null control cells (COS-1) and AKR1C2-transfected cells. Phenyl ketone 1 is a cell-permeable fluorogenic probe that permits a direct, real-time, and operationally simple readout of AKR1C2 enzyme activity in intact mammalian cells. Furthermore, it was demonstrated that probe 1 enables the quantitative examination of physiological substrate 5alpha-dihydrotestosterone ("dark substrate") in situ by means of a two-substrate competitive assay. Similarly, inhibitor potency of physiological (ursodeoxycholate) and synthetic inhibitors (flufenamic acid, ibuprofen, and naproxen) was also readily evaluated.

Fluorogenic metabolic probes for direct activity readout of redox enzymes: Selective measurement of human AKR1C2 in living cells.

Das aktuelle Arsenal von Instrumenten und Verfahren f&uuml;r die kontinuierliche &Uuml;berwachung und Bildgebung der Redox Stoffwechselwege im Zusammenhang mit intakten Zellen beschr&auml;nkt. Fluorogenic Substrate erm&ouml;glichen direkte Messung der Enzymaktivit&auml;t in-situ; im Gegensatz zu Proteasen und Exo-GLYKOSIDASEN gibt es jedoch keine einfachen Richtlinien f&uuml;r die Gestaltung der selektive Sonden f&uuml;r Redox metabolische Enzyme. Hier stellen wir Redox Sonde 1 und seine hohen Selektivit&auml;t in lebenden Zellen f&uuml;r menschliche Hydroxysteroid Dehydrogenases (HSDs) der Aldo-Keto-Reduktase (AKR)-Superfamilie zu demonstrieren. AKR1C Isoformen f&uuml;hren mehrere Funktionen, die unter denen anderem der Stoffwechsel der potente Steroidhormone ist gut dokumentiert. Dar&uuml;ber hinaus ist Ausdruck dieser Enzyme reagieren auf zellul&auml;rer Stress und Pathogenese, einschlie&szlig;lich Krebs. Unsere Sonde Redox-Sensitive optische Schalter, basiert auf dem Paar-ein Keton-Alkohol-Redox-Ereignis um einen tiefgreifenden Wandel in Fluoreszenz. Die hohe Selektivit&auml;t der Phenyl-Keton 1 f&uuml;r AKR1C2 &uuml;ber die viele endogene Reductases in S&auml;ugetier-Zellen wurde durch einen quantitativen Vergleich der Stoffwechselrate zwischen null Kontrolle (COS-1) und die AKR1C2-transfected Zellen. 1-Phenyl-Keton ist eine Zelle-durchl&auml;ssigen Fluorogenic-Sonde, die eine direkte, in Echtzeit und operativ leicht Auslesen der AKR1C2 Enzym-Aktivit&auml;t in den S&auml;ugetier-Zellen intakt l&auml;sst. Dar&uuml;ber hinaus wurde nachgewiesen, Sonde 1 erm&ouml;glicht die quantitative Untersuchung der physiologischen Substrat 5alpha-Dihydrotestosteron (&quot;dunkles Substrat&quot;) in-situ mittels einer wettbewerbsf&auml;higen zwei-Substrat-Assay. Ebenso wurde auch bereitwillig Hemmer Potenz der physiologischen (Ursodeoxycholate) und synthetischen Inhibitoren (Flufenamic S&auml;ure, Ibuprofen und Naproxen) ausgewertet.

Fluorogenic metabolische Sonden f&uuml;r direkte Aktivit&auml;t Ablesung Redox-Enzyme: selektive Messung der menschlichen AKR1C2 in lebenden Zellen.

The nervous system transmits signals between neurons via neurotransmitter release during synaptic vesicle fusion. In order to observe neurotransmitter uptake and release from individual presynaptic terminals directly, we designed fluorescent false neurotransmitters as substrates for the synaptic vesicle monoamine transporter. Using these probes to image dopamine release in the striatum, we made several observations pertinent to synaptic plasticity. We found that the fraction of synaptic vesicles releasing neurotransmitter per stimulus was dependent on the stimulus frequency. A kinetically distinct "reserve" synaptic vesicle population was not observed under these experimental conditions. A frequency-dependent heterogeneity of presynaptic terminals was revealed that was dependent in part on D2 dopamine receptors, indicating a mechanism for frequency-dependent coding of presynaptic selection.

Fluorescent false neurotransmitters visualize dopamine release from individual presynaptic terminals.

Das Nervensystem &uuml;bertr&auml;gt Signale zwischen Neuronen &uuml;ber Neurotransmitter-Freisetzung w&auml;hrend synaptische Vesikel Verschmelzung. Um Neurotransmitter Aufnahme zu beobachten und Pressemitteilung vom einzelnen pr&auml;synaptischen Klemmen direkt, gestalteten wir fluoreszierende falsche Neurotransmitter als Substrate f&uuml;r die synaptische Vesikel Monoamin-Transporter. Verwenden diese Pr&uuml;fpunkte auf Bild-Dopamin-Release im Striatum, haben wir mehrere Beobachtungen, die synaptische Plastizit&auml;t. Wir fanden, dass der Anteil der synaptische Vesikel, die Freigabe Neurotransmitter pro Impuls die Impuls-Frequenz abh&auml;ngig war. Kinetisch unterschiedliche &quot;Reservieren&quot; synaptische Vesikel Einwohner wurde unter diesen Versuchsbedingungen nicht beobachtet. Eine frequenzabh&auml;ngige Heterogenit&auml;t der pr&auml;synaptischen Terminals wurde aufgedeckt, dass D2-Dopamin-Rezeptoren, angibt, einen Mechanismus f&uuml;r die frequenzabh&auml;ngige Kodierung der pr&auml;synaptischen Auswahl teilweise abh&auml;ngig war.

Article	Year
On the relationship between the substitution pattern of thiobenzanilides and their antimycobacterial activity. Farmaco (SocietÃ chimica italiana : 1989)\| PubMed ID: 12385530	2002
Synthesis and structure-antifungal activity relationships of 3-aryl-5-alkyl-2,5-dihydrofuran-2-ones and their carbanalogues: further refinement of tentative pharmacophore group. Bioorganic & medicinal chemistry\| PubMed ID: 12788357	2003
New tools for molecular imaging of redox metabolism: development of a fluorogenic probe for 3 alpha-hydroxysteroid dehydrogenases. Journal of the American Chemical Society\| PubMed ID: 14982413	2004
Two-photon induced uncaging of a reactive intermediate. Multiphoton in situ detection of a potentially valuable label for biological applications. The Journal of organic chemistry\| PubMed ID: 15760198	2005
Fluorogenic metabolic probes for direct activity readout of redox enzymes: Selective measurement of human AKR1C2 in living cells. Proceedings of the National Academy of Sciences of the United States of America\| PubMed ID: 16938874	2006
Fluorescent false neurotransmitters visualize dopamine release from individual presynaptic terminals. Science (New York, N.Y.)\| PubMed ID: 19423778	2009

Vojtech Balsanek

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